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| <template>
<div class="guaguale">
<p>一等奖</p>
<canvas
id="canvas"
width="500"
height="1000"
@mousedown="down"
@mouseup="up"
@mousemove="move"
>
您的浏览器不支持canvas！
</canvas>
</div>
</template>
<script>
export default {
data() {
return {
flag:false,
lx:'',
ly:''
}
},
mounted() {
this.guagua();
},
methods:{
guagua() {
let cv = document.getElementById("canvas"),
p = document.getElementsByTagName("p")[0];
//设置中奖几率
let num = 10000 * Math.random(),
result = "";
if (num < 1000) {
// result = "三等奖";
}
if (num < 50) {
// result = "二等奖";
}
if (num < 5) {
// result = "一等奖";
}
p.innerText = result;
try {
let ct = cv.getContext("2d");
//绘制背景色
ct.fillStyle = "skyblue";
ct.fillRect(0, 0, 500, 1000);
//设置绘制状态
ct.lineCap = "round"; //设置线条两端为圆弧
ct.lineJoin = "round"; //设置线条转折为圆弧
ct.lineWidth = 60;
/*设置新绘制清除新绘制内容和原内容的重叠区域*/
ct.globalCompositeOperation = "destination-out";
} catch (e) {
console.log(e);
}
},
down(e) {
this.flag = true;
this.lx = e.offsetX;
this.ly = e.offsetY;
},
up() {
this.flag = false;
},
move(e) {
if (this.flag) {
let cv = document.getElementById("canvas");
let ct = cv.getContext("2d");
ct.beginPath();
ct.moveTo(this.lx, this.ly);
ct.lineTo(e.offsetX, e.offsetY);
ct.stroke();
ct.closePath();
//更新坐标
this.lx = e.offsetX;
this.ly = e.offsetY;
}
}
}
}
</script>
<style lang="scss" scoped>
#canvas {
/* canvas 默认宽高 300*150
css设置的宽高，只能设置canvas对象在页面显示的大小。
并不能增加画布内部的像素数
*/
border: 1px solid black;
/* width: 500px;
height: 500px; */
margin: 0 auto;
position: absolute;
left: 0;
top: 0;
}
.guaguale {
width: 500px;
height: 500px;
background: url("../../assets/dou.png") no-repeat;
background-size: 100% 100%;
position: relative;
}
.guaguale p {
font-size: 50px;
line-height: 500px;
text-align: center;
width: 100%;
}
</style>
|